"Once I know you're okay, I will."

She loves Sara, but her sister is bleeding from the neck currently -- right now she needs to make sure that gets taken care of. She wraps an arm around Waverly's waist to support her sister as she walks her back. She keeps an eye out for any trouble, and Peacemaker still in her other hand just in case -- but for now at least the coast is clear.

It's easier to focus on what needs to be done, on helping her sister than her anger or betrayal.